RT 5.0 Translate into other languages

I have tried the basics like
@LexiconLanguages = qw(pt_PT) unless (@LexiconLanguages);
in RT_Siteconfig and it doesnt do anything.
@LexiconLanguages = qw(pt) unless (@LexiconLanguages);
… the same …
So the question is simple
What do I need to do ? … precisely … to translate RT into another language ?
Did I miss an install ? do I need to edit something else ? or should that line have worked ?
Please help.

You can change which language RT is in by going to your user preferences page, the “About me” section

Thanks for the reply.
2 issues
a) users have no settings or preferences but when i log in as root i can see the option you mentioned . how do i allow users to see this option ?
b) not everything is completly translated … any idea where the files are so i can manually do this ?

The shipped language files are in /opt/rt5/share/po/ (in RT5’s preferred directory hierarchy at least - if you or a distro package installed RT elsewhere you might have to hunt a bit). If you want to make local modifications the best way is to create a /opt/rt5/local/po directory, copy the language file(s) you want to edit to there, edit them and the flush your Mason cache and restart your web server.